The Cochrane Library: more systematic reviews on nutrition needed

The knowledge and relevance of nutrition as well as the demand for well-funded advices increase. The Cochrane Collaboration plays a leading role within the evidence-based medicine and practice. We advocate therefore more specialized nutritional interest within the Cochrane Collaboration. In case 'Nutrition' needs more attention within the Cochrane Library, one of the first priorities is deciding about whether to include non-randomized studies into the Specialized Register and generating lists of journals to handsearch for such a Specialized Register. Preparatory to these activities an inventory of Nutritional content within the Cochrane Library is needed. We estimate that reviews directly related to nutrition and those of borderline interest to nutrition represent less than 4% of all published reviews in The Cochrane Library.

Interventions for preventing obesity in children

BACKGROUND

Obesity prevention is an international public health priority. The prevalence of obesity and overweight is increasing in child populations throughout the world, impacting on short and long-term health. Obesity prevention strategies for children can change behaviour but efficacy in terms of preventing obesity remains poorly understood.

OBJECTIVES

To assess the effectiveness of interventions designed to prevent obesity in childhood through diet, physical activity and/or lifestyle and social support.

SEARCH STRATEGY

MEDLINE, PsycINFO, EMBASE, CINAHL and CENTRAL were searched from 1990 to February 2005. Non-English language papers were included and experts contacted.

SELECTION CRITERIA

Randomised controlled trials and controlled clinical trials with minimum duration twelve weeks.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Twenty-two studies were included; ten long-term (at least 12 months) and twelve short-term (12 weeks to 12 months). Nineteen were school/preschool-based interventions, one was a community-based intervention targeting low-income families, and two were family-based interventions targeting non-obese children of obese or overweight parents. Six of the ten long-term studies combined dietary education and physical activity interventions; five resulted in no difference in overweight status between groups and one resulted in improvements for girls receiving the intervention, but not boys. Two studies focused on physical activity alone. Of these, a multi-media approach appeared to be effective in preventing obesity. Two studies focused on nutrition education alone, but neither were effective in preventing obesity. Four of the twelve short-term studies focused on interventions to increase physical activity levels, and two of these studies resulted in minor reductions in overweight status in favour of the intervention. The other eight studies combined advice on diet and physical activity, but none had a significant impact. The studies were heterogeneous in terms of study design, quality, target population, theoretical underpinning, and outcome measures, making it impossible to combine study findings using statistical methods. There was an absence of cost-effectiveness data.

AUTHORS' CONCLUSIONS

The majority of studies were short-term. Studies that focused on combining dietary and physical activity approaches did not significantly improve BMI, but some studies that focused on dietary or physical activity approaches showed a small but positive impact on BMI status. Nearly all studies included resulted in some improvement in diet or physical activity. Appropriateness of development, design, duration and intensity of interventions to prevent obesity in childhood needs to be reconsidered alongside comprehensive reporting of the intervention scope and process.

Use of surgery to aid weight reduction-experience of two regions of Northern England: a database study

OBJECTIVE

To determine the usage of surgery in the management of obesity.

DESIGN

Analysis of routine statistics.

DATA SOURCES

Hospital Episode Statistics extract held by Public Health Observatories. GEOGRAPHICAL AREAS: Two Government Office Regions in England with a population of 7.6 million. TIME PERIOD: Data analysed in the study covered the 6 y 1996/1997-2001/2002.

RESULTS

The availability and uptake of surgery for obesity in the two regions was hugely variable. The overall utilisation of the procedures examined (OPCS operation codes: G30.1, G30.2, G32.10, G61.00) was 5.6 per million per annum, but ranged by Primary Care Trust from zero (the case in eight of the 50 PCTs in the two regions) to 24.0 operations per million per year. The rates of access to this surgery differed over six-fold between the two regions (1.4 operations per year per million population to 7.9 operations per year per million population). The PCTs with the highest rates of surgery, were those closest to the large providers of service.

CONCLUSIONS

Access to this intervention is highly variable. Primary Care Trusts in England and service providers need to ensure that there is appropriate access to this effective procedure in carefully selected cases. The surgical expertise required for these operations could be concentrated in fewer centres.

Omega 3 fatty acids for prevention and treatment of cardiovascular disease

BACKGROUND

It has been suggested that omega 3 (W3, n-3 or omega-3) fats from oily fish and plants are beneficial to health.

OBJECTIVES

To assess whether dietary or supplemental omega 3 fatty acids alter total mortality, cardiovascular events or cancers using both RCT and cohort studies.

SEARCH STRATEGY

Five databases including CENTRAL, MEDLINE and EMBASE were searched to February 2002. No language restrictions were applied. Bibliographies were checked and authors contacted.

SELECTION CRITERIA

RCTs were included where omega 3 intake or advice was randomly allocated and unconfounded, and study duration was at least six months. Cohorts were included where a cohort was followed up for at least six months and omega 3 intake estimated.

DATA COLLECTION AND ANALYSIS

Studies were assessed for inclusion, data extracted and quality assessed independently in duplicate. Random effects meta-analysis was performed separately for RCT and cohort data.

MAIN RESULTS

Forty eight randomised controlled trials (36,913 participants) and 41 cohort analyses were included. Pooled trial results did not show a reduction in the risk of total mortality or combined cardiovascular events in those taking additional omega 3 fats (with significant statistical heterogeneity). Sensitivity analysis, retaining only studies at low risk of bias, reduced heterogeneity and again suggested no significant effect of omega 3 fats. Restricting analysis to trials increasing fish-based omega 3 fats, or those increasing short chain omega 3s, did not suggest significant effects on mortality or cardiovascular events in either group. Subgroup analysis by dietary advice or supplementation, baseline risk of CVD or omega 3 dose suggested no clear effects of these factors on primary outcomes. Neither RCTs nor cohorts suggested increased relative risk of cancers with higher omega 3 intake but estimates were imprecise so a clinically important effect could not be excluded.

REVIEWERS' CONCLUSIONS

It is not clear that dietary or supplemental omega 3 fats alter total mortality, combined cardiovascular events or cancers in people with, or at high risk of, cardiovascular disease or in the general population. There is no evidence we should advise people to stop taking rich sources of omega 3 fats, but further high quality trials are needed to confirm suggestions of a protective effect of omega 3 fats on cardiovascular health. There is no clear evidence that omega 3 fats differ in effectiveness according to fish or plant sources, dietary or supplemental sources, dose or presence of placebo.

Improving management of obesity in primary care: cluster randomised trial

OBJECTIVE

To evaluate a training programme intended to improve the management of obesity, delivered to general practice teams.

DESIGN

Cluster randomised trial.

SETTING

Northern and Yorkshire region of England.

PARTICIPANTS

44 general practices invited consecutively attending obese adults to participate; 843 patients attended for collection of baseline data and were subsequently randomised.

INTERVENTION

4.5 hour training programme promoting an obesity management model.

MAIN OUTCOME MEASURES

Difference in weight between patients in intervention and control groups at 12 months (main outcome measure) and at 3 months and 18 months; change in practitioners' knowledge and behaviour in obesity management consultations.

RESULTS

Twelve months after training the patients in the intervention group were 1 (95% confidence interval--1.9 to 3.9) kg heavier than controls (P = 0.5). Some evidence indicated that practitioners' knowledge had improved. Some aspects of the management model, including recording weight, target weight, and dietary targets, occurred more frequently in intervention practices after the training, but in absolute terms levels of implementation were low.

CONCLUSION

A training package promoting a brief, prescriptive approach to the treatment of obesity through lifestyle modification, intended to be incorporated into routine clinical practice, did not ultimately affect the weight of this motivated and at risk cohort of patients.

Relative efficacy of differential methods of dietary advice: a systematic review

BACKGROUND

Dietary advice to lower blood cholesterol may be given by a variety of means. The relative efficacy of the different methods is unknown.

OBJECTIVE

The objective was to assess the effects of dietary advice given by dietitians compared with advice from other health professionals, or self-help resources, in reducing blood cholesterol in adults.

DESIGN

We performed a systematic review, identifying potential studies by searching the electronic databases of the Cochrane Library, MEDLINE, EMBASE, CINAHL, Human Nutrition, Science Citation Index, and Social Sciences Citation Index. We also hand-searched relevant conference proceedings, reference lists in trial reports, and review articles. Finally, we contacted experts in the field. The selection criteria included randomized trials of dietary advice given by dietitians compared with advice given by other health professionals or self-help resources. The main outcome was difference in blood cholesterol between the dietitian group compared with other intervention groups. Inclusion decisions and data extraction were duplicated.

RESULTS

Eleven studies with 12 comparisons met the inclusion criteria. Four studies compared dietitians with doctors, 7 with self-help resources, and 1 with nurses. Participants receiving advice from dietitians experienced a greater reduction in blood total cholesterol than those receiving advice from doctors (-0.25 mmol/L, 95% CI -0.37, -0.12 mmol/L). There was no statistically significant difference in change in blood cholesterol between dietitians and self-help resources (-0.10 mmol/L, 95% CI -0.22, 0.03 mmol/L).

CONCLUSIONS

Dietitians appeared to be better than doctors at lowering blood cholesterol in the short to medium term, though the difference was small (about 4%), but there was no evidence that they were better than self-help resources or nurses.

Controlled clinical trial of two weight reducing diets in a NHS hospital dietetic outpatient clinic - a pilot study

BACKGROUND

Outpatient dietary weight reduction for obesity is unsatisfactory. The objective of this study was to compare the efficacy of an energy prescription diet with usual care (a healthy eating diet) in adult overweight patients referred to a NHS hospital dietetic outpatient clinic, in terms of weight change over 12 weeks.

METHODS

Controlled clinical trial (systematic allocation).

RESULTS

Of the 53 patients who attended their first appointment, 27 completed the trial. Mean weight loss (kg) after 12 weeks was 4.2 (sd 3.8) on the energy prescription diet (n = 16) and 6.0 (sd 2.8) on the healthy eating diet (n = 11).

CONCLUSIONS

Patients on a weight reducing diet based on energy prescription or healthy eating lost, on average, clinically significant amounts of body weight by 12 weeks. Mean weight loss was greater by about 50% in the healthy eating group and supports the development of a larger trial to estimate true effect [corrected].

Review of methods used to estimate non-milk extrinsic sugars

BACKGROUND

Those sugars in foods, which are potentially damaging to dental health, were classified by the Committee on Medical Aspects of Food Policy (COMA) as non-milk extrinsic sugars (NMES). The NMES include sugars outside the cellular structure of a food, excluding the sugars naturally present in milk and milk products. The NMES should contribute no more than 10% of energy intake (Department of Health, 1991). A number of studies have been published where NMES content of foods has been estimated. The purpose of this study was to carry out a comprehensive literature review using a methodical search strategy in order to identify the different methods that have been used for NMES estimation.

METHODS

Databases searched were MEDLINE, EMBASE, Health-CD and Health Management Information Consortium (HMIC) (as sources of UK government and other official publications).

RESULTS

In total, 32 publications were found in which NMES values were reported and five different methods to estimate NMES were identified. No published method provided sufficient information to clearly differentiate between methods and inadequate detail was given to support replication of any of the methods. Of these five methods, The Ministry of Agriculture, Fisheries and Food (MAFF) have published three different descriptions of methods of NMES estimation used in UK national dietary surveys published since 1989. However, one method has been described consistently in the National Diet and Nutrition surveys published since 1994.

CONCLUSIONS

A single, uniform approach to the estimation of NMES for application in nutritional surveys is essential for cross-comparison between surveys. The results show that there is a clear need for one standardized approach for the estimation of NMES in foods.

Interventions for treating obesity in children

BACKGROUND

The prevalence of overweight and obesity is increasing in child populations throughout the world. Obesity in children has significant short and long term health consequences.

OBJECTIVES

To assess the effects of a range of lifestyle interventions designed to treat obesity in childhood.

SEARCH STRATEGY

We searched CCTR, MEDLINE, EMBASE, CINAHL, PsychLIT, Science Citation Index, Social Science Citation Index. Each database was searched from 1985 to July 2001. We also contacted experts in child obesity treatment.

SELECTION CRITERIA

We selected randomised controlled trials of lifestyle interventions for treating obesity in children with a minimum of six months duration. Examples of lifestyle interventions include dietary, physical activity and/or behavioural therapy interventions, with or without the support of associated family members. Interventions from any setting and delivered by any professional were considered. However, interventions that specifically dealt with the treatment of eating disorders were excluded.

DATA COLLECTION AND ANALYSIS

Two of our research team independently assessed trial quality and extracted data. Authors of the included studies were contacted for additional information where this was appropriate.

MAIN RESULTS

We included 18 randomised controlled trials with 975 participants. Many studies were run from a specialist obesity clinic within a hospital setting. Five studies (n=245 participants) investigated changes in physical activity and sedentary behaviour. Two studies (n=107 participants) compared problem-solving with usual care or behavioural therapy. Nine studies (n=399 participants) compared behavioural therapy at varying degrees of family involvement with no treatment or usual care or mastery criteria and contingent reinforcement. Two studies (n=224 participants) compared cognitive behavioural therapy with relaxation.Most of the studies included in this review were too small to have the power to detect the effects of the treatment. We did not conduct a meta-analysis since so few of the trials included the same comparisons and outcomes. Therefore, we synthesised the results in a narrative format.

REVIEWER'S CONCLUSIONS

Although 18 research studies were found, most of these were very small studies drawn from homogenous, motivated groups in hospital settings and so generalisable evidence from them is limited. In conclusion, there is a limited amount of quality data on the components of programs to treat childhood obesity that favour one program over another. Further research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required. We conclude that no direct conclusions can be drawn from this review with confidence.

Dietitians' views of overweight and obese people and reported management practices

OBJECTIVES

To examine dietitians' views of overweight and obese people, to explore the role of level of severity on these perceptions (overweight vs. obesity), and to explore the relationship between dietitians' views and their reported weight management practices.

DESIGN

An independent measures survey, questioning dietitians about either overweight or obese people.

PARTICIPANTS

One-hundred and eighty-seven members of the British Dietetic Association.

MEASUREMENTS

A questionnaire exploring beliefs about the causes, attitudes, perceptions of responsibility and reported weight management practices.

RESULTS

Physical inactivity was identified as an important causative factor for both overweight and obesity. Mood, eating too much of the wrong foods, repeated dieting and interpersonal factors were also seen as relatively important for both groups. Attitudes were mixed, but were generally neutral to positive. The most negative attitudes were described in terms of perceived reduced self-esteem, sexual attractiveness and health. Dietitians rated obese people more negatively than overweight people. They viewed both overweight and obese people as being responsible for their excess weight. They also reported very similar management practices for overweight and obese people. Beliefs about the causes of overweight explained more of the variance in practice than dietitians' attitudes towards or perceived responsibility of overweight and obese people. However, these associations were not consistent and strong, and other factors not investigated here are likely to have a greater influence on weight management practices.

Obesity: diagnosis, prevention, and treatment; evidence based answers to common questions

Paediatric obesity is now common in the UK, as in other developed countries. A literature search was conducted and evidence based answers to five frequently answered questions sought. Recommendations for diagnosis are given. Although there is no conclusive evidence that the condition is preventable, a number of treatment approaches are promising.

An updated systematic review of interventions to improve health professionals' management of obesity

The objective of this article was twofold (1) to determine the existence and effectiveness of interventions to improve health professionals' management of obesity or the organization of care for overweight and obese people; and (2) to update a previous systematic review on this topic with new or additional studies. The study design was a systematic review of intervention studies, undertaken according to standard methods developed by the Cochrane Effective Practice and Organization of Care (EPOC) Group. Participants were trained health care professionals and overweight and obese patients. The measurements were objective measures of health professionals' practice and behaviours, and patient outcomes including satisfaction, behaviour, psychological factors, disease status, risk factors and measures of body weight, fat, or body mass index (BMI). Twelve studies were included in the original review. A further six were included in this update. Six of the 18 studies were randomized controlled trials of health professional-oriented interventions (such as the use of reminders and training) and one was a controlled before-and-after study to improve collaboration between a hospital clinic and general practitioners (GPs). Ten randomized controlled trials and two controlled clinical trials of interventions comparing either the deliverer of weight-loss interventions or the setting of the delivery of the intervention, were identified. The heterogeneity and generally limited quality of identified studies make it difficult to provide recommendations for improving health professionals' obesity management. To conclude, at present, there are few solid leads about improving obesity management, although reminder systems, brief training interventions, shared care, inpatient care and dietitian-led treatments may all be worth further investigation. Therefore, decisions for the improvement of provision of services must be based on the existing evidence on interventions with patients and good clinical judgement. Further research is needed to identify cost-effective strategies for improving the management of obesity. A full version of this review (including detailed descriptions of the included studies and their methodological quality, and results and excluded studies tables) is available in the Cochrane Library. The Cochrane Library is a database of systematic review and other evidence on the effects of health care, continuously updated as new information emerges. It is available on CD ROM from Update Software. For further information see: http://www.update-software.com/cochrane.

Dietary fat intake and prevention of cardiovascular disease: systematic review

OBJECTIVE

To assess the effect of reduction or modification of dietary fat intake on total and cardiovascular mortality and cardiovascular morbidity.

DESIGN

Systematic review.

DATA SOURCES

Cochrane Library, Medline, Embase, CAB abstracts, SIGLE, CVRCT registry, and biographies were searched; trials known to experts were included.

INCLUDED STUDIES

Randomised controlled trials stating intention to reduce or modify fat or cholesterol intake in healthy adult participants over at least six months. Inclusion decisions, validity, and data extraction were duplicated. Meta-analysis (random effects methodology), meta-regression, and funnel plots were performed.

RESULTS

27 studies (30 902 person years of observation) were included. Alteration of dietary fat intake had small effects on total mortality (rate ratio 0.98; 95% confidence interval 0.86 to 1.12). Cardiovascular mortality was reduced by 9% (0.91; 0.77 to 1.07) and cardiovascular events by 16% (0.84; 0.72 to 0.99), which was attenuated (0.86; 0.72 to 1.03) in a sensitivity analysis that excluded a trial using oily fish. Trials with at least two years' follow up provided stronger evidence of protection from cardiovascular events (0.76; 0.65 to 0.90).

CONCLUSIONS

There is a small but potentially important reduction in cardiovascular risk with reduction or modification of dietary fat intake, seen particularly in trials of longer duration.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction or modification of dietary fat can improve total cholesterol levels, but may also have a variety of effects, both positive and negative, on other cardiovascular risk factors.

OBJECTIVES

The aim of this systematic review was to assess the effect of reduction or modification of dietary fats on total and cardiovascular mortality and cardiovascular morbidity over at least 6 months, using all available randomized clinical trials.

SEARCH STRATEGY

The Cochrane Library, MEDLINE, EMBASE, CAB Abstracts, CVRCT registry and related Cochrane Groups' trial registers were searched through spring 1998, SIGLE to January 1999. Trials known to experts in the field and biographies were included through May 1999.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomized with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) healthy adult humans, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available. Inclusion decisions were duplicated, disagreement resolved by discussion or a third party.

DATA COLLECTION AND ANALYSIS

Rate data were extracted by two independent reviewers and meta-analysis performed using random effects methodology. Meta-regression and funnel plots were used.

MAIN RESULTS

Twenty seven studies were included (40 intervention arms, 30,901 person-years). There was no significant effect on total mortality (rate ratio 0.98, 95% CI 0.86 to 1.12), a trend towards protection form cardiovascular mortality (rate ratio 0.91, 95% CI 0.77 to 1.07), and significant protection from cardiovascular events (rate ratio 0.84, 95% CI 0.72 to 0.99). The latter became non-significant on sensitivity analysis. Trials where participants were involved for more than 2 years showed significant reductions in the rate of cardiovascular events and a suggestion of protection from total mortality. The degree of protection from cardiovascular events appeared similar in high and low risk groups, but was statistically significant only in the former.

REVIEWER'S CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk in trials longer than two years. Lifestyle advice to all those at high risk of cardiovascular disease (especially where statins are unavailable or rationed), and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates.

Dietary advice given by a dietitian versus other health professional or self-help resources to reduce blood cholesterol

BACKGROUND

The average level of blood cholesterol is an important determinant of the risk of coronary heart disease. Blood cholesterol can be reduced by dietary means. Although dietitians are trained to provide dietary advice, for practical reasons it is also given by other health professionals and occasionally through the use of self-help resources.

OBJECTIVES

To assess the effects of dietary advice given by a dietitian compared with another health professional, or the use of self-help resources, in reducing blood cholesterol in adults.

SEARCH STRATEGY

We searched The Cochrane Library (to Issue 2 1999), MEDLINE (1966 to January 1999), EMBASE (1980 to December 1998), Cinahl (1982 to December 1998), Human Nutrition (1991 to 1998), Science Citation Index, Social Sciences Citation Index, hand searched conference proceedings on nutrition and heart disease, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials of dietary advice given by a dietitian compared with another health professional or self-help resources. The main outcome was difference in blood cholesterol between dietitian groups compared with other intervention groups.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Eleven studies with 12 comparisons were included, involving 704 people receiving advice from dietitians, 486 from other health professionals and 551 people using self-help leaflets. Four studies compared dietitian with doctor, seven with self-help resources, and one compared dietitian with nurse. Participants receiving advice from dietitians experienced a greater reduction in blood cholesterol than those receiving advice only from doctors (-0.25 mmol/L (95% CI -0.37, -0.12 mmol/L)). There was no statistically significant difference in change in blood cholesterol between dietitians and self-help resources (-0.10 mmol/L (95% CI -0.22, 0.03 mmol/L)). No statistically significant differences were detected for secondary outcome measures between any of the comparisons with the exception of dietitian versus nurse for HDLc, where the dietitian groups showed a greater reduction (-0.06 mmol/L (95% CI -0.11, -0.01)). No significant heterogeneity between the studies was detected.

REVIEWER'S CONCLUSIONS

Dietitians were better than doctors at lowering blood cholesterol in the short to medium term, but there was no evidence that they were better than self-help resources. The results should be interpreted with caution as the studies were not of good quality and the analysis was based on a limited number of trials. More evidence is required to assess whether change can be maintained in the longer term. There was no evidence that dietitians provided better outcomes than nurses.

Improving health professionals' management and the organisation of care for overweight and obese people

BACKGROUND

Obesity is increasing throughout the industrialised world. If left unchecked it will have major implications for both population health and costs to health services. Health professionals have a key role to play in tackling the obesity problem, but little is known about how they may be encouraged to work more effectively with overweight and obese people.

OBJECTIVES

The main objective was to determine whether health professionals' management or the organisation of care for overweight and obese people could be improved.

SEARCH STRATEGY

We searched the specialised registers of the Cochrane Effective Practice and Organisation of Care Group (May 1997), the Cochrane Depression, Anxiety and Neurosis Group (August 1997), the Cochrane Diabetes Group (August 1997), the Cochrane Controlled Trials Register (September 1997), MEDLINE to January 1998, EMBASE to December 1997, Cinahl (1982 to November 1997), PsycLit (1974 to December 1997), Sigle (1980 to November 1997), Sociofile (1974 to October 1997), Dissertation Abstracts (1861 to January 1998), Conference Papers Index (1973 to January 1998), Resource Database in Continuing Medical Education. We also hand searched seven key journals and contacted experts in the field.

SELECTION CRITERIA

Randomised trials, controlled before-and-after studies and interrupted time series analyses of providers' management of obesity or the organisation of care to improve provider practice or patient outcomes. We addressed three a priori comparisons and a fourth post hoc comparison. 1. Interventions aimed at improving health professionals' management or the delivery of health care for overweight/obese patients are more effective than usual care. 2. Interventions aimed at redressing negative attitudes and related practices towards overweight/obese patients are more effective than usual care. 3. Organisational interventions designed to change the structure of services for overweight/obese people are more effective than educational or behavioural interventions for health professionals. 4. Comparisons of different organisational interventions.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Twelve studies were included involving more than 393 providers and 3392 patients. Four studies were identified for comparison 1. Three were professional-oriented interventions (the use of reminders and training) and the fourth was a study of professional and organisational interventions of shared care. No studies were identified for comparisons 2 or 3. Eight studies were identified for post hoc comparison 4. These compared either the deliverer of weight loss interventions or the setting of interventions. The included studies were heterogeneous and of generally poor quality.

REVIEWER'S CONCLUSIONS

At present, decisions about improving provision of services must be based on the evidence of patient interventions and good clinical judgement. Further research is needed to identify cost effective strategies for improving the management of obesity.

A systematic review of interventions to improve health professionals' management of obesity

OBJECTIVE

To determine the existence and effectiveness of interventions to improve health professionals' management of obesity or the organisation of care for overweight and obese people.

DESIGN

A systematic review of intervention studies, undertaken according to standard methods developed by the Cochrane Effective Practice and Organisation of Care (EPOC) Group.

PARTICIPANTS

Trained health care professionals and overweight and obese patients.

MEASUREMENTS

Objective measures of health professionals' practice and behaviours, and patient outcomes including satisfaction, behaviour, psychological factors, disease status, risk factors, and measures of body weight, fat, or BMI.

RESULTS

Twelve studies that met all the review inclusion criteria were identified. Three were randomised controlled trials of health professional-oriented interventions (such as the use of reminders and training) and one was a controlled before and after study to improve collaboration between a hospital clinic and GPs. A further eight randomised controlled trials were identified of interventions comparing either the deliverer of weight loss interventions or the setting of the delivery of the intervention. The heterogeneity and generally limited quality of identified studies make it difficult to provide recommendations for improving health professionals' obesity management.

CONCLUSIONS

At present, decisions about improving the provision of services for overweight and obese people must be based on the evidence from patient interventions and good clinical judgement. Future research is required to identify cost-effective strategies for improving health professionals' management and the organisation of care for overweight and obese people.

Childhood predictors of adult obesity: a systematic review

OBJECTIVE

To identify factors in childhood which might influence the development of obesity in adulthood.

BACKGROUND

The prevalence of obesity is increasing in the UK and other developed countries, in adults and children. The adverse health consequences of adult obesity are well documented, but are less certain for childhood obesity. An association between fatness in adolescence and undesirable socio-economic consequences, such as lower educational attainment and income, has been observed, particularly for women. Childhood factors implicated in the development of adult obesity therefore have far-reaching implications for costs to the health-services and economy.

SEARCH STRATEGY

In order to identify relevant studies, electronic databases--Medline, Embase, CAB abstracts, Psyclit and Sport Discus-were searched from the start date of the database to Spring 1998. The general search structure for electronic databases was (childhood or synonyms) AND (fatness or synonyms) AND (longitudinal or synonyms). Further studies were identified by citations in retrieved papers and by consultation with experts.

INCLUSION CRITERIA

Longitudinal observational studies of healthy children which included measurement of a risk factor in childhood (<18 y), and outcome measure at least 1 y later. Any measure of fatness, leanness or change in fatness or leanness was accepted. Measures of fat distribution were not included. Only studies with participants from an industrialized country were considered, and those concerning minority or special groups, e.g. Pima Indians or children born preterm, were excluded.

FINDINGS

Risk factors for obesity included parental fatness, social factors, birth weight, timing or rate of maturation, physical activity, dietary factors and other behavioural or psychological factors. Offspring of obese parent(s) were consistently seen to be at increased risk of fatness, although few studies have looked at this relationship over longer periods of childhood and into adulthood. The relative contributions of genes and inherited lifestyle factors to the parent-child fatness association remain largely unknown. No clear relationship is reported between socio-economic status (SES) in early life and childhood fatness. However, a strong consistent relationship is observed between low SES in early life and increased fatness in adulthood. Studies investigating SES were generally large but very few considered confounding by parental fatness. Women who change social class (social mobility) show the prevalence of obesity of the class they join, an association which is not present in men. The influence of other social factors such as family size, number of parents at home and childcare have been little researched. There is good evidence from large and reasonably long-term studies for an apparently clear relationship for increased fatness with higher birth weight, but in studies which attempted to address potential confounding by gestational age, parental fatness, or social group, the relationship was less consistent. The relationship between earlier maturation and greater subsequent fatness was investigated in predominantly smaller, but also a few large studies. Again, this relationship appeared to be consistent, but in general, the studies had not investigated whether there was confounding by other factors, including parental fatness, SES, earlier fatness in childhood, or dietary or activity behaviours. Studies investigating the role of diet or activity were generally small, and included diverse methods of risk factor measurement. There was almost no evidence for an influence of activity in infancy on later fatness, and inconsistent but suggestive evidence for a protective effect of activity in childhood on later fatness. No clear evidence for an effect of infant feeding on later fatness emerged, but follow-up to adulthood was rare, with only one study measuring fatness after 7y. Studies investigating diet in childhood were limited and inconc

Randomised controlled trial of novel, simple, and well supervised weight reducing diets in outpatients

OBJECTIVES

To investigate the contribution of novelty and simplicity to compliance with a low energy diet among obese outpatients.

DESIGN

Three arm randomised trial for 16 weeks.

SETTING

NHS hospital obesity clinic.

SUBJECTS

45 patients aged over 17 years with a body mass index >27 who were not diabetic, pregnant, or lactating.

INTERVENTIONS

Conventional 3.4 MJ diet (control), isoenergetic novel diet of milk only, or milk plus one designated food daily. Follow up visit every 4 weeks.

MAIN OUTCOME MEASURE

Weight loss.

RESULTS

Mean weight loss (kg) after 16 weeks on control, milk only, and milk plus diets was 1.7 (95% confidence interval 0.3 to 3.7), 9.4 (5.9 to 12.9), and 7.0 (2.7 to 11.3) respectively. Weight loss on the novel diets was significantly greater than on the control diet.

CONCLUSIONS

Dietary treatment can achieve as much weight loss in obese outpatients over 16 weeks as has been reported for the most successful drug treatment, but compliance with the prescribed diet is poor unless the diet is novel and simple.

Psyllium-enriched cereals lower blood total cholesterol and LDL cholesterol, but not HDL cholesterol, in hypercholesterolemic adults: results of a meta-analysis

We conducted a meta-analysis to determine the effect of consumption of psyllium-enriched cereal products on blood total cholesterol (TC), LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) levels and to estimate the magnitude of the effect among 404 adults with mild to moderate hypercholesterolemia (TC of 5.17-7.8 mmol/L) who consumed a low fat diet. Studies of psyllium cereals were identified by a computerized search of MEDLINE and Current Contents and by contacting United States-based food companies involved in psyllium research. Published and unpublished studies were reviewed by one author and considered eligible for inclusion in the meta-analysis if they were conducted in humans, were randomized, controlled experiments, and included a control group that ate cereal providing </=3 g soluble fiber/d. Eight published and four unpublished studies, conducted in four countries, met the criteria. Analysis of a linear model was performed, controlling for sex and age. Female subjects were divided into two groups to provide a rough estimate of the effect of menopausal status (premenopausal = <50 y, postmenopausal = >/=50 y) on blood lipids. The meta-analysis showed that subjects who consumed a psyllium cereal had lower TC and LDL-C concentrations [differences of 0.31 mmol/L (5%) and 0.35 mmol/L (9%), respectively] than subjects who ate a control cereal; HDL-C concentrations were unaffected in subjects eating psyllium cereal. There was no effect of sex, age or menopausal status on blood lipids. Results indicate that consuming a psyllium-enriched cereal as part of a low fat diet improves the blood lipid profile of hypercholesterolemic adults over that which can be achieved with a low fat diet alone.

Relationship between feeding pattern and body mass index in 220 free-living people in four age groups

OBJECTIVE

To assess the relationship between feeding pattern and body mass index in free-living humans.

DESIGN AND SUBJECTS

Feeding pattern was assessed from 220 7-day weighed dietary records. 187 records were obtained from three separate existing studies, and reanalysed. These studies contained data on three age groups in the British population; Elderly group (n = 88), Middle-aged group (n = 40), Working age group (n = 59). A separate study of 13-14 year olds living in Croydon was conducted from which 33 usable diet records were collected to produce a fourth, Adolescent group.

RESULTS

'Nibbling' and greater energy intakes at breakfast were associated with a lower body mass index (BMI) in the Adolescent group. In the Middle-aged group, greater energy intakes at breakfast and lower energy intakes during the evening were associated with a lower BMI. However, when diet records which produced unreasonably low energy intakes were removed from the analysis, these relationships disappeared except for energy intakes at breakfast and BMI in the Adolescent group.

CONCLUSION

It is suggested that the relationship between feeding pattern and BMI observed in the Adolescent and Middle-aged groups was caused by underestimation of 'habitual' energy intake from snacks and the omission of breakfast by females and those who were overweight. The lack of relationship in the Working age group was attributed to the fact that more individuals in this group appeared to report valid diet records. Reported energy intake was directly related to BMI in the Working age group, but was not related to BMI in the other three age groups. It is concluded that feeding pattern is not a major factor in determining BMI in humans. Also, since snacks have a relatively high sugar and low fat composition compared with meals, it is suggested that biased under-reporting of snacks by the obese could produce spurious results from free-living studies which show that obesity is related to the proportion of energy from fat in the diet.